Various compression devices are known for applying compressive pressure to a patient's limb. These types of devices are used to assist mainly in the prevention of deep vein thrombosis (DVT), vascular disorders and the reduction of oedema. Prior art devices are adapted for use in a hospital setting in which they are used predominantly for the prevention of DVT in patients with a high risk for developing the same. U.S. Pat. Nos. 5,117,812, 5,022,387 and 5,263,473 (The Kendall Company), U.S. Pat. No. 6,231,532 (Tyco International Inc.), U.S. Pat. No. 6,440,093 (McEwen, et al.) and U.S. Pat. No. 6,463,934 (Aircast Inc.) disclose such devices.
Compression therapy is used in the treatment of venous leg ulcers. The treatment relies on the compression achieving a reduction in oedema and improved return of blood via the venous system. This in turn reduces the residence time for blood supplied to the lower limb and the severity of ischaemic episodes within the limb that can result in tissue breakdown.
Compression of the foot can be achieved by a pneumatic compression device. The known devices apply pressure to the foot and to the rest of the limb through a thick cuff which is large, bulky and powered mainly by electricity. The known devices not only affect patient mobility but are also aesthetically unacceptable to many patients. For instance the device can prevent the wearing of the patient's ordinary shoes and clothes meaning that the patient is housebound and unable to walk. In the hospital devices, these disadvantages are not apparent because the patient is largely confined to bed.
A problem in providing an aesthetically acceptable foot cuff is one of supplying the pneumatic fluid to the cuff. In the hospital devices of the prior art, pneumatic fluid is supplied to the cuffs through a network of pipes without consideration to the patient being mobile, wearing normal clothing or wearing a shoe. Even if the patient is able to put their shoe on with the cuff in place in a deflated state, the shoe may prevent inflation of the cuff in the areas where pressure is required as the shoe may block the path for the passage of pneumatic fluid. If a tube is used to supply the fluid to, for instance, the arch of the foot, the shoe may collapse or kink the tube and may cause pressure points on the foot.
In addition, a problem with the devices of the prior art is that the cuff is generally cylindrical and applies pressure over the whole of its surface to the foot, meaning that the mobility of the ankle is reduced making walking difficult even if the patient can wear a shoe and inflate the cuff.
Pneumatic compression devices do, however, have advantages in particular over compression bandages. They provide an effective treatment, while deflated, the inflatable cuff or cuffs are easy to apply to the patient's foot and the pressure is more readily controlled and monitored. Also, they are not subject to the effect of radius where the level of compression depends on the circumference of the limb so that high pressure and low pressure spots occur at the ankle where the radius under the bandage varies. The effect of radius is a fundamental limitation of elasticated bandages and stockings. In addition, it is difficult to apply pressure to the heel of the foot with an elastic bandage and this is an area in which ulcers occur. With elastic bandages, applying pressure to the heel means that mobility in the ankle is reduced as the bandage applies pressure over the whole ankle. This reduction in mobility impairs venous return as the patient is unable to walk normally.
There, thus, exists a need for a foot cuff, which focuses the pressure applied by the cuff to those areas where ulcers are prevalent and limits inflation of the cuff in the surrounding areas so that the patient is able to wear their ordinary shoes and clothes with the cuff inflated. There is also a need for a means of supplying pneumatic fluid to a foot cuff so that inflation is focused on certain areas and the patient is allowed to be mobile and wear ordinary shoes without interrupting the supply of fluid to the cuff. There is also a need for a foot cuff that enables the application of pressure in a manner that is flexible enough to allow the treatment of various indications from one device.